#include <cstdio>
#include <cstring>

const int _m = 50 + 10;
int T, n, m;
char s[_m], t[_m];
int match[_m], flag[_m];
int ans[_m];
int z[_m][_m];

bool find(int u)
{
    for (int v = 1; v <= m; v++)
    {
        if (z[u][v])
        {
            if (! flag[v])
            {
                flag[v] = true;
                if (match[v] == -1 || find(match[v]))
                {
                    match[v] = u;
                    ans[u] = v;
                    return true;
                }
            }
        }
    }
    return false;
}

int hungary()
{
    memset(match, -1, sizeof(match));
    int ans = 0;
    for (int i = m; i >= 1; i--)
    {
        memset(flag, 0, sizeof(flag));
        ans += find(i);
    }
    return ans;
}

int main()
{
    scanf("%d", &T);
    while (T--)
    {
        scanf("%d%d", &n, &m);
        for (int i = 1; i <= m; i++)
        {
            for (int j = 1; j <= m; j++)
            {
                z[i][j] = 1;
            }
        }
        for (int i = 1; i <= n; i++)
        {
            scanf("%s", s + 1);
            scanf("%s", t + 1);
            for (int j = 1; j <= m; j++)
            {
                for (int k = 1; k <= m; k++)
                {
                    if (s[j] != t[k])
                    {
                        z[j][k] = 0;
                    }
                }
            }
        }
        if (hungary() == m)
        {
            for (int i = 1; i < m; i++)
            {
                printf("%d ", ans[i]);
            }
            printf("%d\n", ans[m]);
        }
        else
        {
            puts("-1");
        }
    }
    return 0;
}